000 AXPZ20 KNHC 281536 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SUN NOV 28 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1500 UTC. ...ITCZ... INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N85W TO 07N93W TO LOW PRES NEAR 10N104W TO LOW PRES NEAR 10N112W TO 09N140W. SCATTERED MODERATE CONVECTION WITHIN 120 NM N OF AXIS BETWEEN 103W AND 106W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 122W AND 130W. ...DISCUSSION... W OF 110W... A 1031 MB SURFACE HIGH IS CENTERED N OF THE AREA NEAR 37N140W...AND IS SHIFTING SE BEHIND A COLD FRONT THAT EXTENDS FROM NORTHERN BAJA TO 28N125W. SHIP OBSERVATIONS OFF SOUTHERN CALIFORNIA INDICATE 20 TO 25 KT NW WINDS ARE FOLLOWING THE FRONT. THE FRONT WILL WEAKEN AS IT SHIFTS SE TODAY...AND DISSIPATE THROUGH CENTRAL BAJA BY EARLY MON. THE FRESH TO STRONG WINDS BEHIND THE FRONT WILL PERSIST AND ENVELOPE THE AREA ALONG AND WEST OF THE ENTIRE BAJA COAST OUT TO 130W...ACCOMPANIED BY N SWELL OF 8 TO 13 FT. ELSEWHERE N OF 12N W OF 115W...ASCAT DATA SHOW FRESH TRADES CURRENTLY IN PLACE...AND THESE WILL LIKELY PERSIST FOR THE NEXT SEVERAL DAYS AS THE HIGH PRES TO THE NORTH SHIFTS E TOWARD THE CALIFORNIA COAST. SEAS WILL RUN 8 TO 11 FT TONIGHT AND MON N OF 12N W OF 115W. MEANWHILE...A WEAK SURFACE TROUGH IS ANALYZED ALONG THE ITCZ S OF 14N AT 111W DRIFTING WEST. THE GFS AND ECMWF SHOW THIS FEATURE PERSISTING ALONG THE ITCZ THROUGH MIDWEEK...ALTHOUGH THE GFS SHOWS IT A LITTLE MORE AMPLIFIED AS IT MOVES W REACHING 125W BY WED. THE MAIN IMPACT WILL BE SLIGHTLY HIGHER TRADES MON AND TUE N OF THE TROUGH...ALONG WITH CLUSTERS OF SHOWERS AND TSTMS WITH 120 NM OF THE TROUGH. CLUSTERS OF ONGOING CONVECTION WILL PERSIST ALONG THE ITCZ S OF 120W WHERE GOOD TRADE WIND CONVERGENCE WILL CONTINUE. E OF 110W... STRONG GAP WIND FLOW THROUGH THE GULF OF TEHUANTEPEC CONTINUES TO DIMINISH. A 00Z WINDSAT PASS SHOWED WINDS ONLY 20 TO 25 KT WINDS...AND THIS HAS LIKELY DIMINISHED FURTHER SINCE THEN. THE SALINA CRUZ OBSERVATION ON THE TEHUANTEPEC COAST IS DOWN TO 15 KT CURRENTLY. COLD AIR ADVECTION IN THE SW GULF OF MEXICO HAS TAPERED OFF AS HIGH PRES OVER EASTERN U.S. SHIFTS EAST AHEAD OF LOW PRES MOVING INTO THE CENTRAL PLAINS. LIGHT FLOW WILL PERSIST THROUGH LATE TUE...WHEN THE NEXT COLD FRONT PUSHES THROUGH THE GULF OF MEXICO AND INTO THE GULF OF TEHUANTEPEC AND ADJACENT WATERS. THIS WILL BE A STRONGER FRONT...AND STORM CONDITIONS ARE POSSIBLE BY WED MORNING. WEAK LOW PRES IS CENTERED NEAR 10N104W ACCOMPANIED BY SCATTERED MODERATE CONVECTION. THIS MAY HAVE BEEN ENHANCED IN PART BY THE EASTERLY GAP WIND FLOW ORIGINATING OUT OF TEHUANTEPEC...AND IS EXPECTED TO WEAKEN TODAY AS IT DRIFTS WEST. FURTHER SOUTH...SHIP OBSERVATIONS NEAR THE GULF OF PAPAGAYO INDICATE OVERNIGHT DRAINAGE FLOW IS ALLOWING GAP WINDS TO PULSE TO 20 KT. GLOBAL MODELS SHOW BROAD LOW PRES FORMING OVER THE SW CARIBBEAN AND SOUTHERN CENTRAL AMERICA MON AND TUE. SW FLOW WILL INCREASE S OF COSTA RICA AND PANAMA TUE...FEEDING INTO THE DEVELOPING LOW PRES. LOOKING AHEAD...THE MODELS INDICATE LOW PRES FORMING OFF THE PACIFIC COAST OF COSTA RICA WED...ENHANCING WINDS AND SEAS. GULF OF CALIFORNIA... A COLD FRONT IS MOVING INTO THE NORTHERN EXPANSES OF THE GULF OF CALIFORNIA THIS MORNING...BRINGING FRESH W TO NW FLOW. THIS WILL DIMINISH TONIGHT AS THE FRONT WEAKENS. NW WINDS WILL INCREASE TOMORROW AS THE HIGH PRES BEHIND THE FRONT BUILDS EAST INTO THE GREAT BASIN NORTH OF THE AREA. SURFACE RIDGING CONTINUES TO DOMINATE A MAJORITY OF THE DISCUSSION AREA N OF 15N W OF 110W WHILE A WEAK COLD FRONT IS ANALYZED FROM NEAR 30N120W TO 28N130W OVER THE FAR NE PORTION OF THE FORECAST WATERS. A FAIRLY EXTENSIVE AREA OF FRESH TO STRONG TRADE WINDS IS NOTED WITHIN THE SOUTHERN PERIPHERY OF THE RIDGE PER EARLIER SCATTEROMETER PASSES FROM WINDSAT AND ASCAT. THESE WINDS ARE FORECAST TO PERSIST MAINLY FROM 10N TO 25N W OF 120W THROUGH EARLY NEXT WEEK AS HIGH PRESSURE SETTLES INTO THE REGION FROM THE NORTH IN THE WAKE OF THE ADVANCING WEAK COLD FRONT. THE FRONT WILL CONTINUE TO PUSH SOUTHEAST...GRADUALLY DISSIPATING IN THE PROCESS AND EXTEND FROM THE NORTHERN BAJA NEAR 30N115W TO 28N126W BY 28/1200 UTC SUNDAY...THEN DISSIPATE OVER THE FORECAST WATERS BY LATE SUNDAY. 20 TO 25 KT NW TO N WINDS AND A NEW BATCH OF NW SWELL WHICH WILL BUILD SEAS TO AROUND 12 FT WILL FOLLOW THE FRONT DOWN THE BAJA COAST SUNDAY. FURTHER SOUTH...A WEAK 1011 MB LOW PRESSURE REMAINS WITHIN THE ITCZ NEAR 10N102W. WEST OF THE LOW CENTER...A COUPLE OF WEAK SURFACE TROUGHS EXTEND ALONG 112W AND 121W. ISOLATED MODERATE CONVECTION IS NOTED BETWEEN THE TWO BOUNDARIES FROM 11N TO 14N BETWEEN 114W AND 119W. WITH THE COLD FRONT PASSAGE ACROSS THE GULF OF CALIFORNIA...NW WINDS ARE FORECAST TO SPREAD THEIR INFLUENCE SOUTHWARD AND INCREASE OVER THE GULF THROUGH THE FORECAST PERIOD WITH SEAS GRADUALLY BUILDING TO 8 FT BY EARLY TUESDAY. GAP WINDS... WINDS REMAIN BELOW GALE FORCE IN THE GULF OF TEHUANTEPEC REGION AND WILL CONTINUE TO GRADUALLY DECREASE TO BELOW 20 KT BY EARLY MONDAY AS HIGH PRESSURE OVER THE GULF OF MEXICO RAPIDLY SHIFTS EASTWARD...AND WINDS VEER TO THE SOUTH ACROSS THE WESTERN GULF OF MEXICO. LOOKING AHEAD...A STRONGER COLD FRONT IS EXPECTED TO IMPACT THE WESTERN GULF OF MEXICO BY LATE TUESDAY AND DELIVER ANOTHER ROUND OF GALE FORCE WINDS TO THE GULF OF TEHUANTEPEC... POSSIBLY APPROACHING STORM STRENGTH WEDNESDAY. GAP WINDS THROUGH THE GULF OF PAPAGAYO WILL PULSE TO 20 KT IN THE EARLY MORNING HOURS WITH THE ASSISTANCE OF NOCTURNAL DRAINAGE FLOW AND SOME ADDED ENHANCEMENT FROM EASTERLY PRESSURE GRADIENT FLOW LOCATED OVER THE SW CARIBBEAN SEA. $$ HUFFMAN